相关论文: Chromospheric activity of the double-lined spectro…

We present analysis of medium resolution optical spectra and long term V band photometry of four cool stars, BD+13 5000, BD+11 3024, TYC 3557-919-1 and TYC 5163-1764-1. Our spectroscopic analysis reveals that the stars are giant or…

We present the first in a series of papers that attempt to investigate the relation between binarity, magnetic activity, and chemical surface abundances of cool stars. In the current paper, we lay out and test two abundance analysis methods…

We report on a three year spectroscopic monitoring program of the H-alpha emission in the massive X-ray binary LS I +65 010 = 2S 0114+650, which consists of a B-supergiant and a slowly rotating X-ray pulsar. We present revised orbital…

Stellar activity cycles reveal continuous relaxation and induction of magnetic fields. The activity cycle is typically traced through the observation of cyclic variations in total brightness or Ca H&K emission flux of stars, as well as…

Using a time series of high-resolution spectra and high-quality multi-colour photometry, we reconstruct surface maps of the primary component of the RS CVn type rapidly rotating eclipsing binary, SV Cam (F9V + K4V). We measure a mass ratio,…

The first detailed photometric and spectroscopic analysis of the G-type eclipsing binary KM UMa is presented, which indicates that the system is a short-period detached eclipsing binary. The radial velocity curves were calculated using the…

Strong spectral lines are useful indicators of stellar chromospheric activity. They are physically linked to the convection efficiency, differential rotation, and angular momentum evolution and are a potential indicator of age. However, for…

We study chromospheric oscillations including umbral flashes and running penumbral waves in a sunspot of active region (AR) using scanning spectroscopy in H-alpha and Ca II 8542A, with the Fast Imaging Solar Spectrograph (FISS) at the 1.6…

The re-emission in the cores of the Ca II H & K and H$\alpha$ lines, are well known proxies of stellar activity. However, these activity indices probe different activity phenomena, the first being more sensitive to plage variation, while…

This study depends on KIC 9641031 eclipsing binary system with a chromospherically active component. There are three type variations, such as geometrical variations due to eclipses, sinusoidal variations due to the rotational modulations…

This work is part of the BinaMIcS project, the aim of which is to understand the interaction between binarity and magnetism in close binary systems. All the studied spectroscopic binaries targeted by the BinaMIcS project encompass hot…

We monitored the chromospheric activity in the Ca II H & K lines of 13 solar-type stars (including the Sun); 8 of them over three years at the CFHT and 5 in a single run at the VLT. Ten of the 13 targets have close planetary companions. All…

We report on the results of a new spectroscopic monitoring campaign of the quasar PG 0026+129 at the Calar Alto Observatory 2.2m telescope from July 2017 to February 2020. Significant variations in the fluxes of the continuum and…

We introduce an iterative spectral disentangling technique combined with Doppler imaging in order to recover surface temperature maps for both components of double-lined active binary systems. Our method provides an opportunity to separate…

We report the results of a comprehensive study of the spectroscopic binary (SB2) system HD 34736 hosting two chemically peculiar (CP) late B-type stars. Using new and archival observational data, we characterise the system and its…

HD 81809 has one of the highest quality activity cycles from the sample of stars synoptically observed in the Mount Wilson Observatory HK Project. However, this object is in fact a binary system, raising the question as to which of the…

We study the evolution of chromospheric line and continuum emission during the impulsive phase of the X-class SOL2014-09-10T17:45 solar flare. We extend previous analyses of this flare to multiple chromospheric lines of Fe I, Fe II, Mg II,…

We have investigated the spectral behaviour of II Peg binary system in the ultraviolet band by using International Ultraviolet Explorer observations over fifteen years. The ultraviolet observations show indication of flare activity in the…

Understanding stellar activity in M dwarfs is fundamental to improving our knowledge of the physics of stellar atmospheres and for planet search programmes. High levels of stellar activity (also with flare events) can cause additional…

High resolution echelle spectra of PW And (HD~1405) have been taken during eight observing runs from 1999 to 2002. The detailed analysis of the spectra allow us to determine its spectral type (K2V), mean heliocentric radial velocity (V_hel…